Bucket elevator



p 1967 c. D. FISHER 3,343,654

BUCKET ELEVATOR Filed Oct. 11, 1965 5 Sheets-Sheet 1 INVENTOR'. a J0 CHESTER DONALD FISHER ATTYS.

3 Sheets-Sheet 2 INVENTOR'.

CHESTER DONALD FISHER Sept. 26, 1967 Filed Oct. 11, 1965 lllillnllllllll iii.

ATTY S.

p 1967 C. D. FISHER 3,343,654

BUCKET ELEVATOR Filed Oct. 11, 1965 5 Sheets-Sheets l I I I I 5 I I l l I L? l H I l I i: i 1

I J INVENTOR 6/ CHESTER DONALD FISHER ATTYS.

United States Patent 3,343,654 BUCKET ELEVATGR Chester Bonatd Fisher, l'viuncy, Pa. 17756 Filed Oct. 11, 1965, Ser. No. 394,543 9 Claims, (Cl. 193-207) This invention relates generaly to conveyors and more particularly to a type of conveyor commonly known as a bucket elevator used for conveying particulate or granular material from one location to another.

Bucket elevators of the type to which the present invention relates generally comprise an elongated housing, in some instances consisting of hollow spaced apart leg sections or leggings, drive and driven pulleys mounted at opposite ends of the housing and an endless belt carrying a plurality of buckets mounted for movement in an endless path between the pulleys. The elevator further includes a boot at one end of the housing communicating with the leg sections and having an inlet opening to receive material and a head at the opposite end of the housing having a discharge outlet. By this arrangement, material fed into the boot which is usually at a low level is conveyed by the buckets continuously to the discharge outlet in the head which is usualy disposed vertically above the boot at a much higher level.

The bucket elevator of the present invention is characterized by novel features of construction and arrangement providing several functional advantages in this type of equipment. For example, one of the features of the present invention is the provision of air jets in the boot designed to agitate material in the boot and insure the complete purging of the boot. These air jets are disposed to clean out the buckets during the purging operation. This particular feature is important when changing from one type of material to another in the elevator. In some instances, if the boot -is not completely cleaned out, the residual material may contaminate the next type of material being conveyed in the elevator.

In accordance with another feature of the bucket elevator of the present invention, the boot section fioats relative to the leggings automatically to maintain a fixed and close clearance between the outer lip of the bucket and inner enclosing case so as to minimize the residual material to be removed by the air jets, in addition to maintaining a predetermined desired belt tension thereby increasing the belt life and effectively extending the overall life of the elevator. The bucket elevator also incorporates a self-tensioning motor mounting for the drive pulley whereby the transmission means in the form of belts connecting the motor and drive pulley is maintained at the proper tension at all load. This minimizes slippage and insures efiicient and effective operation of the bucket elevator.

A further feature of the bucket elevator of the present invention is the provision of a safety switch which operates automatically to shut off power when the boot pulley slows down below a predetermined angular velocity or stops. By this arrangement, protection against fires caused by pulley friction within a stalled belt is insured.

All of the features discussed above are incorporated in an elevator of comparatively simplified construction so that it is highly economical to manufacture and extremely efficient and comparatively maintenance-free in operation.

Further, the bucket elevator of the present invention is capable of high speed operation to provide high capacities using small and econmical elevator cups.

With the foregoing in mind, an object of the present invention is to provide a bucket elevator which is rugged, durable and of compartively simplified construction so that it is highly economical to manufacture and extremely efiicient, effective and useful for the purposes intended.

Still another object of the present invention is to provide a bucket elevator incorporating means for cleaning the boot section to insure a completely clean unit when changing from one type of material to another.

Still another object of the present invention is to provide a bucket elevator which incorporates automatic shutoff means so that it is extremely safe from friction-caused fires.

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a bucket elevator in accordance with the present invention;

FIG. 2 is an enlarged fragmentary longitudinal sectional view of the bucket elevator shown in FIG. 1 with parts broken away to show the internal construction of the bucket elevator;

FIG. 3 is a fragmentary end view of the bucket elevator of the present invention;

FIG. 4 is a sectional view taken on line 4-4 of FIG. 5;

FIG. 5 is an enlarged sectional view taken on lines 55 of FIG. 2;

FIG. 6 is a fragmentary view showing the mounting arrangement for the drive motor;

FIG. 7 is a side elevational view of the motor mount; and

FIG. 8 is an enlarged sectional view taken through the boot showing the cleaning means for the boot.

Referring now to the drawings and considering first the primary components of the elevator in terms of function, the bucket elevator generally designated by the numeral 19 comprises a housing 12 consisting in the present instance of a pair of elongated, vertically disposed, spaced apart, hollow leg sections or leggings, an ascending leg section 14 and a descending leg section 16, a substantially enclosed boot 18 mounted at the lower terminal ends of the leg sections and a substantially enclosed head 29 mounted at the upper terminal ends of the leg sections. An endless belt 28 mounting a plurality of buckets 36 is supported for movement in an endless path between a drive pulley 24 carried by a stub shaft 24a rotatably journalled in the head 29 and a driven pulley 26 supported on a stub shaft 26a rotatably journalled in the boot 18. Suitable drive means including a motor M and a belt transmission T actuates the head pulley 24 to move the buckets 30 in an endless path in a clockwise direction with respect to FIG. 2. By this arrangement, material delivered to the boot 18 through an inlet hopper 32 is picked up by the buckets 3i conveyed up the ascending leg section 14 and discharged in the head 2% to a suitable conveyor means in the form of a screw conveyor 34 for delivery to another location. One of the leg sections, in the present instance, the ascending leg section 14 has an opening 36 with an access door 38 to facilitate inspection of the belt and buckets.

Considering now more specifically the structural details of the elevator, the boot 13 comprises spaced parallel side walls 40 and 42, an arcuate or curved bottom Wall 44 having a portion 44a conforming to the radius of curvature of the boot pulley 26 and a top cover 46 having suitable openings 48 and 50 to receive the ascending and descending leg sections is and 16 respectively. It is noted that the opening 50 is enlarged to accommodate the inlet hopper 32 formed integrally with the descending leg section 16. Suitable bearings B are mounted in the opposed side walls 40 and 42 of the boot within which the pulley shaft 26a rotates. By this arrangement, the material enters the elevator on the down side of the boot permitting belt speeds of between 600 to 1,000 f.p.m. Thus, the buckets 30' are loaded on the down side in the direction of rotation and it is possible to achieve almost 100% loading of the elevator buckets. This contrasts with some arrangements where the incoming material meets the buckets as they are rising at high speed where it is only possible to obtain fractional loading of the buckets.

The boot, as best illustrated in FIG. 2, is counterweighted by means of weights 60 supported on a rod 62 projecting from the upper face of the top cover 46. The weight 60 can be adjusted so as to add the proper amount of weight to the boot pulley so as to maintain the proper relations between the tension in the up-going strand of belt and the down-coming strand of the elevatorbelt. As the elevator height increases and the weight of material in the up-coming buckets increases, it will be necessary to add increased counterweighting to keep the tight and loose side tensions in proper proportions. Also, if the material being elevated is heavy, the weight carried by the upgoing belt will be increased; consequently, more counterweighting will be necessary again to maintain proper relations between up and down belts. The cup-like cap 66 on the bracket 68 spanning the leg sections and adapted to engage the top of the rod 62 is provided to prevent the boot from falling off the telescoping legs in event of belt failure. Itis not unknown for these elevator belts to fail-that is, pull apart after extended usage. The elevator boot is guided in its up and down movements by the elevator legging, also by the aligning rod 62 and the clearance hole in the bracket 68 spanning the leg sections. This counterweighting arrangement provides an automatic tensioning and take-up for the elevator belt to provide a predetermined constant tension during operation. Thus, the need for an operator to adjust belt tension is eliminated. Moreover, the fire hazard of improper belt tension is also obviated. For example, if the belt tension is too loose and the belt slips on the head or drive pulley 24, the elevator will choke. If the belt slips on the head pulley for an extended duration, the friction generated will cause wear and perhaps failure and in some cases precipitate a fire. Thus, the present arrangement minimizes hazards and increases the life of the belt. The clearance D between the bottom wall of the boot and the line described by the periphery of the buckets during movement through the boot is set at a predetermined fixed close setting.

An adjusting screw 70 is provided in the bracket 72 on one side wall of the boot which engages a projecting lip 74 of the bearing for the boot pulley 26. With this arrangement, it is possible to adjust one of the bearings of the boot pulley 26 so as to properly align the boot pulley with the elevating belt. Once this pulley has been placed in alignment, no further adjustment is necessary. The clearance D is maintained and fixed at as close a distance as is commercially possible to manufacture. With this clearance close, there is a minimum of material in the boot which means the air jets have very little material to move in order to effect cleanout. In the general run of elevator, the boot is fixed and the pulley adjusts up and down relative to the boot. On high elevators, the take-up may be a matter of some to inches and with the takeup in the top position, there would remain 15 inches or better of material in the boot that should be cleaned out when the materials are changed that the elevator is to handle.

In accordance with another feature of the elevator of the present invention, means is provided for purging the boot and buckets when changing operations from one type of material to another. To this end, as best illustrated in FIG. 8, a plurality of nozzles 80 are provided in the boot which have discharge openings 82 directed interiorly of the boot. The nozzles are arranged in the present instance in pairs in each side Wall of the boot, and in the present instance, all of the nozzle openings are directed downwardly so that jets of air are aimed against the curved bottom wall of the boot. By this arrangement, the boot may be purged completely when changing operations from one type of material to another, the jets directed against the bottom wall of the boot serving to agitate or suspend material so that it may be picked up by the buckets. Further it is noted that the turbulence generated by the air jets serves to stir up any accumulation in the buckets thereby to clean out any material which may be retained in the buckets. However, if desired, one or more of the nozzle openings may be directed to discharge a jet of air into the buckets to loosen any material which may be impacted in the bottom of the buckets.

Even though the danger of choking the boot has been minimized in a bucket elevator in accordance with the present invention, another feature of the bucket elevator is the provision of sensing means in the form of a motion switch 84 operatively connected to the boot pulley to sense angular speed thereof. This motion switch 84 may in turn be connected to the motor M for the drive pulley 24 or to a suitable signalling device either to shut off the motor M or set off the signalling device when the angular speed of the boot pulley decreases below a predetermined value. By this arrangement, if there is some malfunction of the feeding apparatus, for example, which might choke the boot, which in turn would slow down or stop rotation of the buckets, the motion switch 84 would sense this condition through the boot pulley and either shut down the motor M or set off a signal which would alert an operator that the elevator is malfunctioning. Further, this arrangement minimizes the risk of damage to the bucket elevator and eliminates a fire hazard which might exist if the drive pulley continues to rotate for too long a period relative to a stalled bucket belt.

Considering now the head section, this section is best illustrated in FIGS. 2 and 3 and comprises a pair of spaced, parallel side walls and 102, and a curved top wall 104 which fans out from the peripheral trace of the buckets to define a discharge chamber 106 at approximately the same height as the center line of the drive pulley to one side thereof. By this arrangement, since the belt operates at relatively high speeds, as the buckets traverse the drive pulley, the material from the buckets has enough velocity to continue vertically for some distance if not restricted. In the present instance, the curved top wall 104 of the head deflects the material into the discharge chamber 106 and from there into the screw conveyor. By reason of the fact that this discharge point is relatively high, the elevator head space requirement is reduced considerably. In conventional bucket elevators which operate at lower belt speeds, it is necessary to house the elevator head in an extra high cupola section for the reason that the discharge level is substantially below the center line of the head pulley. This enlarged cupola is very expensive and since it is not required in the present construction, this is a cost saving factor.

In the present instance the drive means for the drive pulley consists of the motor M having a belt transmission B, the motor usually revolving at approximately five times the head pulley r.p.m. to provide a belt speed of between 600 and 2,000 feet per minute. In other-types of conventional bucket elevators which operate at relatively low speeds, it is necessary to provide a gear reducer and chain or belt drive to get down to the lower speed. Gear reducers are costly and substantially increase the price of the elevator. In the present instance, because of the high speed operation, it is possible to provide a direction drive means by means of V-belt transmission from a high speed motor and thus efiect a considerable economy in this aspect of the bucket elevator. Conventionally, with this type of drive and transmission means, it is necessary to mount the motor on an adjustable base to maintain the belts taut and minimize the possibility of slippage which might present a fire hazard. In the present instance the motor is mounted on a base which is pivotally connected to the head section as at 122. By this arrange ment, a reaction torque in the motor tightens the belt. In other words the harder the motor pulls, the tighter the belt transmission. Further, even if the elevator pulley should lock, the motor will stall, no slippage taking place on the transmission belt. This, of course, positively protects the drive from slippage under any and all conditions of loading.

While a particular embodiment of the present invention has been illustrated and described herein, it is not intended to limit the invention and changes and modifications may be made therein within the scope of the following claims.

What is claimed is:

1. A bucket elevator comprising an elongated, generally enclosed housing including a boot at one end having spaced apart sidewalls and a bottom wall and a head at the opposite end, means defining an inlet opening in the boot, means defining a discharge outlet in the head, means supporting a plurality of buckets for movement in an endless path in said housing to convey material fed to the housing through said inlet opening in the boot to said discharge outlet in the head, and means for purging the boot and buckets including at least one nozzle mounted in each sidewall of the boot having discharge openings disposed interiorly of the boot and adapted to be connected to a suitable air supply source, said nozzle discharge openings being directed downwardly to discharge jets of air against the bottom wall of the boot thereby to suspend material in the boot so that it may be picked up by the buckets and said discharge openings also positioned relative to the buckets to direct jets of air interiorly of the buckets thereby to efiFect loosening of any material in the buckets to completely clean the elevator.

2. A bucket elevator as claimed in claim 1 wherein said housing includes spaced apart ascending and descending hollow leg sections between the boot and head and wherein said boot is mounted for movement relative to said leg sections.

3. A bucket elevator as claimed in claim 2 including an inlet hopper formed integrally with the descending leg section in communication with said inlet opening in the boot.

4. A bucket elevator as claimed in claim 2 including means for guiding the boot for movement relative to said leg sections comprising an aligning rod mounted on said boot engaging in a cap member mounted on a bracket spanning the leg sections.

5. A bucket elevator for mounting on a support structure comprising an elongated, generally enclosed housing including spaced apart ascending and descending hollow leg sections, a boot freely suspended at one end of said leg sections and a head at the opposite end of said leg sections, means defining an inlet opening in the boot, means defining a discharge outlet in the head, a drive pulley mounted for rotation about a fixed axis in the head, a driven pulley mounted in the boot, an endless belt mounting a plurality of buckets supported between said pulleys, drive means for actuating said drive pulley to move said belt in an endless path to convey material fed to the housing through said inlet opening in the boot to said discharge outlet in the head, said leg sections telescoping in said boot and said boot and driven pulley axis 6 mounted for movement relative to said leg sections in a manner to provide a constant clearance between the buckets and the boot and means for counterweighting the boot thereby to provide automatic tensioning and takeup for the belt.

6. A bucket elevator as claimed in claim 5 wherein said inlet opening is disposed in the descending leg section of the housing.

7. A bucket elevator as claimed in claim 5 wherein said head comprises a pair of spaced parallel sidewalls and a curved top wall which fans out from the peripheral trace of the buckets to define a discharge chamber at approximately the same height as the center line of the drive pulley to one side thereof.

8. A bucket elevator for mounting on a support structure comprising an elongated, generally enclosed housing including spaced apart ascending and descending hollow leg sections, a boot freely suspended at one end of said leg sections and a head at the opposite end of said leg sections, means defining an inlet opening in the boot, means defining a discharge outlet in the head, a drive pulley mounted in the head, a driven pulley mounted in the boot, an endless belt mounting a plurality of buckets supported between said pulleys, drive means for actuating said drive pulley to move said belt in an endless path to convey material fed to the housing through said inlet opening in the boot to said discharge outlet in the head, said boot mounted for movement relative to said leg sections in a manner to provide a constant clearance between the buckets and boot and means for counterweighing the boot thereby to provide automatic tensioning and take-up for the belt, sensing means operatively connected to the boot pulley to sense angular speed thereof and means operatively connecting the sensing means to said drive means for the drive pulley to render said drive means inoperative when the driven pulley velocity decreases below a predetermined value.

9. A bucket elevator as claimed in claim 8 wherein said drive means consists of a motor having a belt transmission connected to said drive pulley and including mounting means for the motor which is pivotally connected to the head whereby the desired tension is maintained in the belt transmission thereby to minimize the possibility of slippage.

References Cited UNITED STATES PATENTS 207,626 9/ 1878 Sargent 198193 263,634 8/ 1882 Webster 198-229 880,303 2/ 1908 Hetherington r 198207 1,160,523 11/1915 Marrow 198'207 1,942,590 12/1934 Binger 198231 2,394,638 2/ 1946 Schrader 198-208 3,107,385 10/ 1963 Muller l5316 3,225,903 12/1965 Piemont 198-206 EVON C. BLUNK, Primary Examiner.

RICHARD E. AEGERTER, Assistant Examiner. 

1. A BUCKET ELEVATOR COMPRISING AN ELONGATED, GENERALLY ENCLOSED HOUSING INCLUDING A BOOT AT ONE END HAVING SPACED APART SIDEWALLS AND A BOTTOM WALL AND A HEAD AT THE OPPOSITE END, MEANS DEFINING AN INLET OPENING IN THE BOOT, MEANS DEFINING A DISCHARGE OUTLET IN THE HEAD, MEANS SUPPORTING A PLURALITY OF BUCKETS FOR MOVEMENT IN AN ENDLESS PATH IN SAID HOUSING TO CONVEY MATERIAL FED TO THE HOUSING THROUGH SAID INLET OPENING IN THE BOOT TO SAID DISCHARGE OUTLET IN THE HEAD, AND MEANS FOR PURGING THE BOOT AND BUCKETS INCLUDING AT LEAST ONE NOZZLE MOUNTED IN EACH SIDEWALL OF THE BOOT HAVING DISCHARGE OPENINGS DISPOSED INTERIORLY OF THE BOOT AND ADAPTED TO BE CONNECTED TO A SUITABLE AIR SUPPLY SOURCE, SAID NOZZLE DISCHARGE OPENINGS BEING DIRECTED DOWNWARDLY TO DISCHARGE JETS OF AIR AGAINST THE BOTTOM WALL OF THE BOOT THEREBY TO SUSPEND MATERIAL IN THE BOOT SO THAT IT MAY BE PICKED UP BY THE BUCKETS AND SAID DISCHARGE OPENINGS ALSO POSI- 